Delete Duplicate Rows In SQL

Removing duplicate rows from a table is a common task in database management. Duplicate data can lead to inconsistencies and inaccuracies in your analysis. SQL provides several ways to identify and eliminate these duplicates. A crucial step is defining which columns constitute a duplicate. For example, if you have a table of customer orders, you might consider two orders to be duplicates if they share the same customer ID and order date. The method you choose depends on the size of your table and the specific columns you want to consider for duplication. A simple approach is to use the `ROW_NUMBER()` window function to assign a unique rank to each row based on the duplicate columns. Then, you can filter out rows with a rank greater than 1. Alternatively, you can use `DELETE` statements with `WHERE` clauses that leverage `GROUP BY` and aggregate functions. The choice of method often depends on the specific database system you are using, as some systems might have more efficient ways to handle large datasets.